h0=figure('toolbar','none',...
 'position',[200 150 450 350],...
 'name','实例24');
 subplot(2,2,1)
 z=peaks;
 ribbon(z)
 title('Figure1')
 subplot(2,2,2)
 [x,y,z]=peaks(15);
 [dx,dy]=gradient(z,0.5,0.5);
 contour(x,y,z,10)
 hold on
 quiver(x,y,dx,dy)
 hold off
 title('Figure2')
 subplot(2,2,3)
 [x,y,z]=peaks(15);
 [nx,ny,nz]=surfnorm(x,y,z);
 surf(x,y,z)
 hold on
 quiver3(x,y,z,nx,ny,nz)
 hold off
 title('Figure3')
 subplot(2,2,4)
 x=rand(3,5);
 y=rand(3,5);
 z=rand(3,5);
 c=rand(3,5);
 fill3(x,y,z,c)
 grid on
 title('Figure4')